134 VEGETABLE COLOURS. 



at the red end. The property which begins at the 

 blue end hinders oxidation, and in some cases re- 

 stores Oxidized bodies to their former state. 



When vegetables are in a state of vigorous and 

 healthy action, they absorb or drink up the red rays 

 of the sun's light, and return the green to the eye ; 

 and the red light, or that invisible oxidizing agency 

 which accompanies the red end of the spectrum, 

 facilitates the combination of the oxygen of the 

 atmosphere with the surplus carbon of the plants, and 

 also forms the acid juice of unripe fruits; while 

 when they decay, and the oxidation ceases, they 

 give out the yellow or the red rays, or the russety 

 and brown tints, which are various mixtures of red, 

 yellow, and green. Fruits too, which are almost all 

 green in their growing states, receive the yellows and 

 reds, and sometimes pass into black, or absorb the 

 entire light, get very sweet and mellow, and soon 

 decay. Coe's golden drop, or any of the plums 

 which ripen to a golden orange, spotted with red, 

 are so far instances of the progress of this action 

 of light upon fruits or of fruits upon light. While 

 green they are very austere ; but as the green fades 

 into yellow, the austerity diminishes ; and when they 

 begin to be spotted with red, they have little or no 

 austerity. These changes are not, however, uni- 

 versal, or even general ; for many of the sweetest 

 fruits that we have are green when they are ripe, 

 and red vegetables are often the sourest of their 

 class : so that, though the light may be the agent in 

 these cases, its action is modified by the nature of 

 the plant ; and it may return the red rays from being 

 already saturated with, and as well as from ceasing 

 to elaborate, acid juice. 



The philosophy of light is, however, a very ob- 

 scure and imperfect philosophy ; and there are not 

 many parts of knowledge in which theories are more 

 likely to lead us wrong. The observation of it has 

 the advantage of being, perhaps, the most pleasing 





